Phytochemical Characterization and Biological Assessment of Geranium robertianum L. Ethanolic Extract on Human Salivary Gland Carcinoma Cells

Overview

This study investigates the phytochemical composition and biological activity of an ethanolic extract derived from aerial parts of Geranium robertianum L., a traditional medicinal plant with limited scientific documentation. The extract was characterized for phenolic and flavonoid content, antioxidant capacity, elemental composition, antibacterial properties, and cytotoxic effects against human salivary gland carcinoma cells.

Methods and approach

Phytochemical analysis was conducted using standard colorimetric assays to quantify total phenolics and flavonoids. Antioxidant activity was assessed through three complementary methods: DPPH radical scavenging, ABTS radical scavenging, and ferric reducing antioxidant power (FRAP). Elemental composition was determined via metal analysis. Antibacterial efficacy was evaluated against both Gram-positive and Gram-negative bacterial strains using comparative assessment against levofloxacin as a control. Cytotoxic potential was examined on A253 human salivary gland carcinoma cells through dose-response analysis, morphological observation, and measurement of reactive oxygen species (ROS) accumulation and apoptotic marker activation (caspase-3/7 and caspase-9).

Key Findings

The extract demonstrated elevated concentrations of phenolic compounds and flavonoids. Among the three antioxidant assays employed, ABTS methodology yielded the highest antioxidant capacity measurement. Elemental analysis revealed Fe as the predominant metal at 363.65 ± 4.18 μg/g, followed by Zn, Mn, Ni, and Cr, while As, Co, Pb, and Cd concentrations remained below detection thresholds. Antibacterial testing showed moderate inhibitory activity against both Gram-positive and Gram-negative bacterial strains with inhibition zones comparable to levofloxacin, with the exception of notably reduced efficacy against Pseudomonas aeruginosa. In cellular assays, the extract exhibited dose-dependent antiproliferative effects on A253 cells, induced morphological alterations, and increased intracellular ROS levels alongside elevated caspase-3/7 and caspase-9 activity.

Implications

The phytochemical profile of G. robertianum L. ethanolic extract, characterized by substantial phenolic and flavonoid content, correlates with demonstrated antioxidant and antimicrobial properties. The absence of hazardous heavy metals below detection limits supports the safety profile of the extract under the tested conditions. The moderate antibacterial activity observed across multiple bacterial strains provides preliminary support for traditional medicinal applications, though strain-specific variation warrants further investigation.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.